Ambient Seismic Noise Tomography of Heterogeneous Geological Formations
Ambient seismic noise tomography is a unique tool suitable for characterizing the velocity structure of various geologically complex regions. To demonstrate this capability, we analyzed 30 days of vertical component short period seismic data from the karstic Santa Fe River Sink-Rise system in north-central Florida. We applied power spectral density estimates and frequency-wavenumber analysis to characterize noise source biases in the tomography. We then extracted Rayleigh wave group velocity dispersion measurements from empirical Green’s functions estimated through phase cross-correlation and phase-weighted stacking. Finally, we inverted the dispersion measurements at various periods, yielding a model of the aquifer’s seismic velocity structure. Our results reveal layering with varying group velocities aligning with a priori hydrostratigraphic knowledge. Notable findings include the base of the aquifer and dolostone semiconfining units characterized by elevated velocities relative to the overall mean velocity. Furthermore, we identified low-velocity upper layers likely expressing zones of extensive karstification. We demonstrate that ambient seismic noise tomography is a robust tool applicable for the characterization and validation of the near-surface structure, including physical properties, identification of unknown features, and the location and continuity of units. Additionally, we are applying the capabilities of ambient noise tomography and signal analysis to the Nevada National Security Sites. Through this endeavor, we aim to enhance our knowledge of the site’s subsurface velocity structure, contributing to a broader understanding of geological contexts with implications for various applications. This work was done by Mission Support and Test Services, LLC, under Contract No. DENA0003624 with the U.S. Department of Energy and the National Nuclear Security Administration Office of Defense Nuclear Nonproliferation. DOE/NV/03624—1843.
Session: Advancements in Forensic Seismology and Explosion Monitoring [Poster Session]
Type: Poster
Room: Exhibit Hall
Date: 5/2/2024
Presentation Time: 08:00 AM (local time)
Presenting Author: Jacob Gochenour
Student Presenter: No
Additional Authors
Jacob Gochenour Presenting Author Corresponding Author gochenja@nv.doe.gov Nevada National Security Sites |
Cleat Zeiler ZeilerCP@nv.doe.gov Nevada National Security Sites |
Susan Bilek susan.bilek@nmt.edu New Mexico Tech |
Andrew Luhmann andrew.luhmann@wheaton.edu Wheaton College |
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Ambient Seismic Noise Tomography of Heterogeneous Geological Formations
Category
Advancements in Forensic Seismology and Explosion Monitoring
Description